ModelAdmin sorting & relationships

Each news article 'has_one' author, and author name is being displayed as a summary field. I would like to be able to have the option of sorting by author name by clicking on the table header, like I can with date/title.

Is this possible? Or have I set my relationships up wrong or something?

Hi:
I need this feature too, by default it allow ID column to be sorted but not all of the other columns , IF you have a look at the Security section-> member table ,you notice that you can sort by E-mail, First name or last name .. so maybe if we find the correct .php files we can find a good example ;)

let me know if you find anything, I also will be looking into it in my free time